KR20230037654A - Apparatus and method for detecting and mitigating cooling leaks - Google Patents

Abstract

The refrigerant leak detection and mitigation system includes a temperature controller that transmits control signals to component controllers and a blower that circulates air. The system includes a leak mitigation controller electrically connected to the temperature control device and component controller. The leak mitigation controller directs incoming power to the temperature control unit. The leak mitigation controller includes a sensor configured to measure refrigerant concentration and a relay configured to (i) connect the temperature control device to incoming power or (ii) connect the blower to incoming power. The leak mitigation controller is configured to measure the refrigerant concentration with a sensor and actuate a relay in response to the measured refrigerant concentration exceeding a threshold to connect the blower to incoming power.

Description

Apparatus and method for detecting and mitigating cooling leaks

The present disclosure relates to heating ventilation and air conditioning (HVAC) systems, and more particularly to detection and mitigation systems for HVAC systems.

<Cross Reference to Related Applications>

This application claims priority from U.S. Utility Patent Application Serial No. 16/930,993, filed July 16, 2020. The entire disclosure of this application is hereby incorporated by reference.

The background description provided herein is intended to generally present the context of the present invention. The work of the presently named inventors is not admitted, either expressly or by implication, as prior art to the present disclosure to the extent set forth in this Background Section, nor any aspect of the description that would otherwise not qualify as prior art at the time of filing.

The most commonly used industrial gases contribute to the global accumulation of greenhouse gases in the Earth's atmosphere, accelerating the rate of global warming. Efforts to limit the use of refrigerants with high global warming potential are ongoing worldwide.

While Al refrigerants (non-toxic and non-flammable) have traditionally been used in HVAC and refrigeration systems, A2L refrigerants (non-toxic and partially flammable) are replacing Al refrigerants in commercial and residential buildings due to their reduced impact on global warming. . Although A2L refrigerants are only partially flammable due to reduced propagation, A2L refrigerants still present a burning hazard.

A refrigerant leak detection and mitigation system includes a temperature controller that sends control signals to component controllers and a blower that circulates air. The system includes a leak mitigation controller electrically connected to the temperature control device and the component controller. The leakage mitigation controller directs incoming power to the temperature control device. The leak mitigation controller includes: a sensor configured to measure refrigerant concentration and a relay configured to (i) connect the temperature control device to the incoming power or (ii) connect the blower to the incoming power. The leak mitigation controller is configured to measure the refrigerant concentration with the sensor and actuate the relay to connect the blower to the incoming power in response to the measured refrigerant concentration exceeding a threshold value.

In a further aspect, the relay maintains the connection between the temperature control device and the incoming power through the leak mitigation controller until the measured refrigerant concentration exceeds the threshold. In a further aspect, the leak mitigation controller operates the blower for a threshold time in response to the measured refrigerant concentration falling below the threshold and controls the relay after the threshold time has elapsed to switch the temperature control device to the incoming power It is configured to connect to

In a further aspect, the temperature control device is selectively connected to the incoming power in a normally open position by the leakage mitigation controller. In a further aspect, the blower is connected to the incoming power in a normally closed position and the sensor de-energizes the coil of the relay in response to the measured refrigerant concentration exceeding the threshold. In a further aspect, the relay is at least one of (i) a single pole double throw relay and (ii) a double pole double throw relay. In a further aspect, the relay includes two or more relays or switches.

In a further aspect, the system includes a compressor. In a further aspect, the component controller is configured to activate the compressor in response to receiving a control signal indicating a cooling request from the temperature control device. In a further aspect, the refrigerant at the measured refrigerant concentration is non-toxic and flammable. In a further aspect, the system includes a remote monitoring device that interfaces with the leak mitigation controller. The remote monitoring device is configured to receive the measured refrigerant concentration from the sensor of the leak mitigation controller and store the measured refrigerant concentration together with a corresponding time at which the measured refrigerant concentration was measured.

In a further aspect, the remote monitoring device monitors the number of times the coil of the relay is energized, and in response to the number of times the coil is energized beyond a threshold, an alert is generated and transmitted to a user device associated with the entity. is configured to In a further aspect, the remote monitoring device monitors blower uptime in response to the measured refrigerant concentration exceeding the threshold and generates an alert in response to the blower uptime exceeding the blower uptime threshold to communicate with the entity. configured to transmit to an associated user device.

In a further aspect, the remote monitoring device is included in the leak mitigation controller. In a further aspect, the remote monitoring device is operated by and included in the temperature control device. In a further aspect, the system includes a backup leakage mitigation controller coupled in series with the leakage mitigation controller. In a further aspect, the backup leak mitigation controller is located in a separate compartment from the leak mitigation controller.

A heating, ventilation, cooling and/or air conditioning (HVAC-R) system includes the refrigerant leak detection and mitigation system of claim 1 .

A method for detecting and mitigating a refrigerant leak includes: causing incoming power to be provided from a temperature control device to a component controller via a leak mitigation controller. The leak mitigation controller includes: a sensor and a relay that (i) connects the temperature control device to the incoming power or (ii) connects the blower to the incoming power and circulates air through the blower. The method may include measuring a refrigerant concentration through the sensor; and connecting the blower to the incoming power by operating the relay in response to the measured refrigerant concentration exceeding a threshold value.

In a further aspect, the method includes using the relay to maintain a connection between the incoming power and the temperature control device through the leak mitigation controller until the measured refrigerant concentration exceeds the threshold. . In a further aspect, the method further comprises the relay to operate the blower for a threshold time in response to the measured refrigerant concentration falling below the threshold and to connect the temperature control device to the incoming power in response to the passage of the threshold time. Including controlling

In a further aspect, the method includes de-energizing a coil of the relay in response to the measured refrigerant concentration exceeding the threshold. In a further aspect, the temperature control device is selectively coupled to the incoming power in a normally open position by the leak mitigation controller and the blower is coupled to the incoming power in a normally closed position. In a further aspect, the relay is at least one of (i) a single pole double throw relay and (ii) a double pole double throw relay.

Further areas of applicability of the present invention will become apparent from the detailed description, claims and drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

The present disclosure will be more fully understood from the detailed description and accompanying drawings.
1 is a block diagram of an exemplary heating, ventilation, and air conditioning (HVAC) system.
2 is a functional block diagram of an upflow air handler unit of an exemplary HVAC system that includes a leak mitigation control module.
3 is a functional block diagram of an upflow air handler unit of an exemplary HVAC system that includes multiple leak mitigation control modules.
4 is a functional block diagram of a downflow air handler unit of an exemplary HVAC system that includes multiple leak mitigation control modules.
5 is a functional block diagram of a leak mitigation control module of an exemplary HVAC system.
6 is a functional block diagram of multiple leak mitigation control modules of an exemplary HVAC system.
7A and 7B are functional block diagrams of leakage mitigation control circuitry within an evaporator of an air handler unit.
8 is a flow diagram illustrating exemplary operation of an exemplary leakage mitigation controller of an HVAC system.
Reference numbers in the drawings may be reused to identify similar and/or identical elements.

According to the present disclosure, a leak mitigation control module detects and detects refrigerant leaks in a heating, ventilation, air conditioning, and refrigeration (HVAC-R) system. It is configured to disable components of the HVAC-R system and activate mitigating components until the relief is relieved. The leak mitigation control module disables system components of the HVAC system by energizing or actuating a relay until the refrigerant concentration falls below a threshold and force a fan or blower on (by connecting the blower directly to power).

The leak mitigation control module includes a leak sensor to detect the concentration of refrigerant in a specific area. To detect refrigerant leaks, leak sensors are placed in areas or locations containing the evaporator coils of the HVAC system. Leak sensors detect the concentration or percentage volume of refrigerant in the evaporator compartment of an HVAC system. Thus, the leak sensor can be calibrated based on the size or volume of the compartment containing the evaporator coil.

A leak sensor in the leak mitigation control module detects a refrigerant leak in response to a refrigerant concentration in the evaporator compartment that exceeds a threshold, eg, 25% of the lower flammability limit (LFL). Relays in the leak mitigation control module are then de-energized, for example by disconnecting power to the temperature control device and/or control module, such as a thermostat ( disconnection) disables power to HVAC system components and forcibly activates the blower by connecting incoming power directly to the blower (and/or other mitigation devices). Since the leak mitigation control module is also directly connected to power, the leak sensor continuously determines the refrigerant concentration in the evaporator compartment. To maintain safe operating conditions, the relays are energized when the HVAC system is powered on and de-energized in response to a refrigerant concentration exceeding a threshold. For example, the configuration described above is fail safe if the HVAC system loses power.

If the refrigerant concentration falls below the threshold, the leak mitigation control module continues to operate the blower for a threshold amount of time, for example 5 minutes. When the threshold time has elapsed, a relay in the leak mitigation control module is energized to deactivate the blower and re-energize the temperature control unit and/or control module. Typically, since the control module supplies power to HVAC system components by connecting to a transformer via the temperature control unit, the leakage mitigation control module is in series with the power connection between the temperature control unit and the control module to break the power connection. connected to

A leak sensor can be configured to detect a specific type of refrigerant. A leak sensor may be configured to detect A2L refrigerant, although other types of refrigerant sensors may be used by the leak mitigation control module. In various implementations, the leak mitigation control module detects other types of flammable refrigerants and performs the mitigation described above. The leak mitigation control module may only operate to detect, monitor and communicate a leak if, for example, a leak sensor detects a leak of non-flammable refrigerant, such as A1 refrigerant. In an example implementation, the leak mitigation control module can sense one or more types of refrigerant. The leak mitigation control module may also include additional sensors. For example, a leak mitigation control module can include temperature and humidity sensors that can help calibrate leak sensor outputs.

In various implementations, the leak mitigation control module directly connects the blower to electrical power to operate the blower at full capacity. In other implementations, the blower may operate at a lower capacity. Also, while the relay is described as a single pole double throw relay (SPDT), other relays may be used, such as a double pole double throw relay (DPDT), multiple single pole double throw relays, and the like. In various implementations, the leak mitigation control module may operate to disconnect or disable some HVAC system components, but not all components.

The leak mitigation control module includes a temperature control module and a furnace control board or air handler board of the HVAC system to control the power connection between the temperature control unit and the HVAC system control module. ) and electrically coupled between control modules such as In normal operation, the HVAC system control module receives control signals from the temperature control device to direct the operation of the HVAC system components. If the leak mitigation control module detects an unacceptable level of refrigerant, the leak mitigation control module will disconnect the power connection between the temperature control unit and the HVAC system control module, sometimes called the R or RC wire, and prevents the operation of HVAC system components by disabling control circuits for HVAC components such as compressors.

In various implementations, the leak mitigation control module may send an indication to a temperature control device or remote monitoring device that a refrigerant leak has been detected either when the HVAC system is operating normally or just before disabling HVAC system components and activating a blower. there is. The indication can be stored in a remote monitoring device to monitor the frequency and magnitude of refrigerant leaks. Additionally or alternatively, the temperature control device may generate a notification for the homeowner or entity associated with the HVAC system indicating that a refrigerant leak has occurred. Similarly, the leak mitigation control module may send an indication to the temperature control device or remote monitoring device that the refrigerant leak has been mitigated when the relay re-energizes the temperature control device and/or control module. A mitigation indication, including the elapsed time between leak and mitigation and the magnitude of the refrigerant leak, may be stored in the remote monitoring device's memory as well as transmitted to the homeowner or entity associated with the HVAC system.

The leak mitigation control module is easily integrated into existing HVAC systems as it does not require any changes to the current control module or schema. Instead, a leak mitigation control module is simply added to the HVAC system, making minor changes to the connection between the temperature control unit, the HVAC system control module, and the blower. Although this disclosure has described leak mitigation control modules being included in HVAC systems, leak mitigation control modules may be used in refrigeration units or other systems that use refrigerants.

As A2L, a partially flammable refrigerant, is being introduced into commercial and residential buildings, standards committees are working to create a set of rules and regulations to govern how A2L refrigerant leaks are detected and mitigated. The leak mitigation control module can be powered by a standard 24 volt (V) AC HVAC transformer and can lock out all HVAC equipment in the event of a leak while turning on mitigation devices including blowers simultaneously.

Overall, the leak mitigation control module operates by selectively shutting off power (power supply) to the temperature control unit or other HVAC controllers, for example the HVAC system control module, in the event of a refrigerant leak and turning that power (power supply) back to its intended Relief device(s), in this case connected directly to the blower. This locks out non-mitigated devices in a simple and cost effective manner. In various implementations, two single pole double throw relays may be implemented in the leak mitigation control module to selectively lock out certain HVAC components.

block diagram

1 is a block diagram of an HVAC system. In this particular example, a forced air system with a gas furnace is shown. Return air is drawn from the building through a filter 104 by a circulator blower 108. Circulation blower 108, also referred to as a fan, is controlled by control module 112. Control module 112 receives signals from temperature control device 116, such as a thermostat. For example, temperature control device 116 may include one or more set point temperatures specified by the user. As noted above, the temperature control device 116 may include a temperature sensor and a humidity sensor.

The temperature control device 116 may instruct the circulating blower 108 to be turned on (auto fan board) always or only when a heat request or cool request is present. In various implementations, the circulating blower 108 can operate at one or more discrete speeds or any speed within a predetermined range. For example, control module 112 may switch one or more switching relays (not shown) to control circulating blower 108 and/or select a speed of circulating blower 108 .

The temperature control device 116 provides heating and/or cooling requests to the control module 112 . When a heating request is made, the control module 112 ignites the burner 120 . Heat from combustion is introduced from heat exchanger 124 to ventilation provided by circulation blower 108. The heated air is supplied to the building and is called supply air.

One ignition option includes a hot surface igniter that heats the surface to a sufficiently high temperature that when gas is introduced the heated surface initiates combustion of the gas. Fuel for combustion, such as natural gas, may be provided by gas valve 128 .

Combustion products are exhausted outside the building, and an induction blower 132 may be turned on prior to ignition of the burner 120 . In high efficiency furnaces, the products of combustion may not be hot enough to have sufficient buoyancy to be discharged via conduction. Thus, induction blower 132 creates a draft for discharging combustion products. The induction blower 132 may continue to operate while the burner 120 is operating. Also, the induction blower 132 may continue to operate for a predetermined time even after the burner 120 is turned off.

A single enclosure, also referred to as an air handler unit, includes filter 104, circulation blower 108, HVAC system control module 112, burner 120, heat exchanger 124, induction blower 132 , expansion valve 140 , evaporator 144 and condensate pan 146 . In various implementations, the air handler unit 136 includes an electrical heating device (not shown) in place of or in addition to the burner 120 . When used in addition to the burner 120, the electric heating device may provide backup or secondary (additional) heat to the burner 120.

As shown in Figure 1, the HVAC system includes a split air conditioning system. The refrigerant is circulated through the compressor 148, the condenser 152, the expansion valve 140, and the evaporator coil 172 of the evaporator 144. Evaporator 144 is a compartment that includes evaporator coil 172 . The evaporator 144 is arranged in series with the supply air so that when cooling is required, the evaporator coil 172 cools the supply air by removing heat from the supply air. During cooling, the evaporator coil 172 circulates a refrigerant that makes the evaporator coil 172 cold (eg, below vent temperature), which condenses water vapor. This water vapor collects in the condensation pan 146 and is drained or pumped out.

Control module 156 receives the cooling request from control module 112 and controls compressor 148 accordingly. Control module 156 may also control condenser fan 160 to increase heat exchange between condenser 152 and outside air. In such a split system, compressor 148, condenser 152, control module 156 and condenser fan 160 are generally located outside the building, often in a single condensing unit 164.

In various implementations, control module 156 may include a run capacitor, a start capacitor, and a contactor or relay. In various embodiments, the starting capacitor may be omitted, for example where condenser unit 164 includes a scroll compressor instead of a reciprocating compressor. Compressor 148 may be a variable displacement compressor and may respond to multiple level cooling requests. For example, a cooling request may indicate a mid-capacity call for cooling or a high capacity call for cooling. Compressor 148 can change its capacity according to cooling demand.

The electrical lines provided to the condensing unit 164 may include a 240 volt main power line and a 24 volt switched control line. A 24 volt control line may respond to the cooling request shown in FIG. 1 . The 24 volt control lines control the operation of control module 112 and control module 156. When the control lines indicate that compressor 148 should turn on, control module 156 connects the 240 volt power supply to compressor 148's motor or compressor 148's motor to drive. to actuate a series of switches to operate compressor 148. Control module 156 may also connect a 240 volt power source (power supply) to condenser fan 160 . In various implementations, condenser fan 160 may be omitted if condensation unit 164 is located underground as part of a geothermal system. The 240 volt mains power arrives on two legs, as is common in the United States, and both legs are connected to the motor of the compressor 148.

1 shows an AC-only unit, other implementations may include heat pump units that further include an accumulator, a reversing valve, an auxiliary heat source, and an outdoor expansion device.

When in the heating (heating) mode, the temperature control device 116 generates a heating request when the temperature measured by the temperature sensor is lower than the lower temperature limit. When in the cooling (cooling) mode, the temperature control device 116 generates a cooling request when the temperature measured by the temperature sensor is higher than the upper limit temperature. The upper temperature limit and the lower temperature limit may be set to the set point temperature plus and minus thresholds (eg, 1, 2, 3, 4, 5 degrees Fahrenheit), respectively. The set point temperature can be set as a default temperature and can be adjusted by receiving user input. The threshold may be set by default and may be adjusted through receiving a user input.

In various implementations, control module 156 or temperature control device 116 may receive a signal from outdoor air temperature (OAT) sensor 168 . The temperature control device 116 may be a communication temperature control device having a WiFi or networking function. In various implementations, the OAT sensor 168 can be located within an enclosure, shielded from direct sunlight and/or exposed to an air cavity that is not directly heated by sunlight. Alternatively or additionally, on-line (including Internet-based via temperature control unit 116) meteorological data based on the geographic location of the building may be used to determine sun load, OAT, relative humidity, particulates, VOCs, carbon dioxide, and the like. can be used to determine

In various implementations, air handler unit 136 will include a transformer (shown in FIGS. 2-7 ) coupled to the incoming AC power line to provide AC power to control module 112 and temperature control device 116 . can For example, the transformer may be a 10:1 transformer and thus provide a 12V or 24V AC power depending on whether the air handler unit 136 operates on normal 120 volts or nominal 240 volts power. Additionally or alternatively, the transformer may be a 5:1 transformer providing 24V AC power if the air handler unit operates on nominal 120 volt power. In this implementation, the temperature control device 116 provides 24VAC power to components of the HVAC system in response to a threshold condition being met.

The control lines may also convey a request for secondary heating and/or secondary cooling, which may be activated when primary heating or primary cooling is insufficient. In dual fuel systems, such as systems that run on electricity or natural gas, control signals related to fuel selection may be monitored.

One or more of these control signals (on the control line) are also sent to the condensation unit 164. In various implementations, condensation unit 164 may include an ambient temperature sensor that generates temperature data. When the condensing unit 164 is located outdoors, the ambient temperature refers to the outside (or outdoor) ambient temperature. A temperature sensor providing the ambient temperature may be located outside the enclosure of the condensing unit 164.

2 is a functional block diagram of an upflow air handler unit of an exemplary HVAC system that includes a leak mitigation control module 176 . For reference and context, the air handler unit 136 of FIG. 1 is shown. The upflow system directs ventilation upward through the air handler unit 136 .

In many systems, the air handler unit 136 is located inside the building, while the condensation unit 164 is located outside the building. However, the present disclosure is not limited to such an arrangement, and the components of air handling unit 136 and condensation unit 164 are located in close proximity to each other or even in one enclosure, often referred to as a packaged unit. It applies to other systems, including systems. A single enclosure may be located inside or outside a building. In various implementations, the air handler unit 136 may be located in a basement, garage, or attic. In a ground source system where heat is exchanged with the earth, the air handler unit 136 and the condensation unit 164 are located in a basement, crawlspace, garage or 1 separated from the ground only by a concrete slab. It can be located near the ground, such as a floor.

As shown in FIG. 2 , a transformer 212 may be connected to the AC line to supply AC power to the HVAC system control module 112 , the leak mitigation control module 176 and the temperature control device 116 . For example, transformer 212 supplies 24V AC power to HVAC system components including control module 112 and temperature control unit 116 . Control module 112 controls operation in response to signals from temperature control device 116 received over the control line. The control lines may include a request for cooling (request cool), a request for heat (request heat) and a request for fan (request fan). The control lines may include a line corresponding to the state of a reversing valve in the heat pump system.

Leak mitigation control module 176 is located within evaporator 144 by means of evaporator coil 172 . Evaporator 144 is a compartment that includes evaporator coil 172 . The leak mitigation control module 176 includes a leak sensor and a relay (eg a safety relay). A leak sensor measures the refrigerant concentration in the evaporator 144. The leak sensor measures the concentration of A2L, a non-toxic and partially flammable refrigerant. However, leak sensors can be used with non-toxic and non-flammable refrigerants such as A1; non-toxic and flammable refrigerants such as A2; Non-toxic and highly flammable refrigerants such as A3; Or you can measure the concentration of a similar version of the refrigerant that is toxic. Additionally, the leak mitigation control module 176 may include other sensors for measuring parameters such as temperature, relative humidity, or barometric pressure.

The leak sensor measures the refrigerant concentration as a percentage of the refrigerant to air mixture in a known volume (here, the evaporator 144). The leak sensor may be calibrated for a particular HVAC system and the size of the compartment in which the leak mitigation control module 176 resides. Leak mitigation control module 176 relays to power down HVAC system components in response to the percentage of refrigerant to air mixture in evaporator 144 that exceeds a lower flammability limit (LFL) or lower explosion limit (LEL) for a given refrigerant. to control Both limits represent the lower limit of the percentage concentration of a refrigerant or flammable gas that can be ignited when mixed with air. For example, a leak sensor in leak mitigation control module 176 may de-energize a relay or actuate a switch in response to a measured refrigerant concentration greater than 25% of the LFL for a given refrigerant in evaporator 144. there is. The relay may be a single pole double throw relay that shuts off power in response to the measured refrigerant exceeding a threshold. The relay is energized under normal operation. However, if the sensed LFL exceeds the threshold, the relay is de-energized. Similarly, if power to the air handler unit 136 or control module 112 is cut, the relay will lose power so that the system as a whole will fail in the event of a loss of power to the control module 112 or the HVAC system. safe)

Leakage mitigation control module 176 receives power directly from transformer 212 . In various implementations, leakage mitigation control module 176 receives power directly from incoming AC power or line voltage (as long as appropriate power circuitry is included in leakage mitigation control module 176). In various implementations, the leakage mitigation control module 176 may have power supplied by the HVAC system control module 112 utilizing onboard power regulation that most control modules already have. In such an implementation, and assuming that control module 112 supplies, for example, 3.3V - 12V DC, leakage mitigation control module 176 converts the 24V AC required by many digital devices into a usable DC power signal. It will not require more extensive power regulation to convert. Other embodiments may include an external AC-DC power supply to power the leakage mitigation control module 176 so that extensive power regulation does not have to be included onboard.

HVAC system components including control module 112 receive power from transformer 212 . The temperature control device 116 controls the operation of the HVAC system components using, for example, a set of switches to connect the HVAC system components to electrical power via the control module 112 . In various implementations, temperature control device 116 may be powered by a battery while still regulating power flow to HVAC system components via control signals to control module 112 . Leakage mitigation control module 176 couples the supplied power to temperature control device 116 when the relays of leakage mitigation control module 176 are in a normally closed state. That is, the relay of leak mitigation control module 176 connects power to temperature control device 116 when the refrigerant concentration is below the threshold. In various implementations, the leakage mitigation control module 176 can selectively disconnect or disconnect power from the control module 112 in conjunction with or instead of the temperature control device 116 .

Accordingly, power leaks from transformer 212 to temperature control device 116 to send control signals to control module 112 for activating and deactivating HVAC system components such as burner 120, circulation blower 108, and the like. It is connected to the temperature control device 116 through a relief controller relay. If the leak sensor in leak mitigation control module 176 measures a refrigerant concentration above a threshold, the relay will de-energize, resulting in a circuit being completed at the normally closed terminals of the relay, which will reduce power to transformer 212 (temperature control). (via unit 116 or directly) to circulation blower 108 and then an open circuit is created at the normally open terminals of the relay to cut power to temperature control unit 116 and disable all other HVAC system components. do.

Thus, once a leak is detected, the temperature control device 116 is powered down and cannot send control signals to the control module 112, thus disabling the operation of the HVAC system components. Power bypasses the temperature control device 116 and is supplied directly to the circulation blower 108 to reduce the refrigerant concentration in that area to mitigate refrigerant leakage. The leak mitigation control module 176 is positioned based on where the refrigerant leak occurs: evaporator coil 172 . In various implementations, the leak mitigation control module 176 may be located in different locations throughout the HVAC system.

3 is a functional block diagram of an upflow air handling unit of an exemplary HVAC system that includes multiple leak mitigation control modules. The leakage mitigation control module 176 of FIG. 2 is shown with another leakage mitigation control module 180 electrically coupled thereto. The second leak mitigation control module 180 is located at a lower point within the HVAC system, another location where a leak can be detected because the refrigerant is heavier than air and sinks when leaking from the system. Either the first leak mitigation control module 176 or the second leak mitigation control module 180 operates the circulation blower 108 or, if another blower (not shown) is included in the HVAC system, the leak mitigation control module 180 ) can be configured to connect the blower power closest to itself. In commercial applications, for example, several evaporator coils may be included in the system; Thus, multiple leak mitigation control modules may be included and configured to operate the nearest blower.

4 is a functional block diagram of a downflow air handling unit of an exemplary HVAC system that includes multiple leak mitigation control modules. The downflow air handler unit operates similarly to the upflow air handler unit 136 of FIGS. 2 and 3 . However, they are rearranged to draw ventilation downward. Accordingly, in the downflow air treatment unit, the leakage mitigation control module 180 may be located at the bottom of the vent of the air supply end to detect refrigerant leakage as the refrigerant falls downward. The HVAC system includes a leak mitigation control module 176 within the evaporator 144 to detect refrigerant leaks where leaks occur. A power wire connecting the leakage mitigation control module 176 and the leakage mitigation control module 180 may be electrically connected between the transformer 212 or the temperature control device 116 and the control modules 112 may be connected in series. That is, only one of the leak mitigation control modules 176 or 180 that measures the refrigerant concentration above the threshold will lock out the HVAC system components (by cutting power) and force the fans on.

5 is a functional block diagram of leak mitigation control module 176 of an exemplary HVAC system. The control module 112 and the leakage mitigation control module 176 receive power from the transformer 212 as indicated by the solid lines connecting the power lines. In various implementations, the leak mitigation control module 176 is electrically connected to the circulation blower 108 through, for example, system control circuitry as indicated by the dotted control lines. Leakage mitigation control module 176 is also electrically coupled to temperature control device 116 as indicated by solid power lines.

Unless leak mitigation control module 176 detects a refrigerant concentration above a threshold, temperature control device 116 will continue to send control signals to control module 112 directing operation, for example through a series of switches. Connect the HVAC system components to incoming AC power according to the instructions. However, in response to detecting a refrigerant concentration above a threshold, leak mitigation control module 176 disconnects power from temperature control device 116 to transformer 212 to prevent HVAC components from being connected to power, thus preventing operation. make it impossible That is, once leakage mitigation control module 176 disconnects temperature control device 116 from incoming AC power, control module 112 can no longer receive a signal from temperature control device 116 .

The leak mitigation control module 176 bypasses the temperature control device 116 and connects the circulating blower 108 directly to the power provided by the transformer 212 to turn on the circulating blower 108 to reduce the concentration of the refrigerant. make it decrease Circulation blower 108 is started in response to leakage mitigation control module 176 detecting a refrigerant concentration above a threshold value. If the leak mitigation control module 176 measures the refrigerant concentration below the threshold, the leak mitigation control module 176 maintains operation of the circulation blower 108 for a threshold amount of time, for example 5 minutes. When the threshold time expires, the control module 176 not only deactivates the bypass of the temperature control unit 116 to the previously set circulation blower 108, but also reconnects the temperature control unit 116 to the transformer 212, All HVAC components are again controlled by the temperature control unit. Leakage mitigation control module 176 uses relays to perform connect and disconnect. Optionally, in various implementations, control module 112 and leak mitigation control module 176 may send control signals indicating when HVAC system components are deactivated or activated, for example, due to a refrigerant leak being detected.

6 is a functional block diagram of multiple leak mitigation control modules of an exemplary HVAC system. The first leakage mitigation control module 304 is electrically coupled to the transformer 212 and the second leakage mitigation control module 308 . The second leakage mitigation control module 308 is electrically coupled to the temperature control device 116 through a power connection line as indicated by solid lines. The first leakage mitigation control module 304 and the second leakage mitigation control module 308 are connected in series to selectively connect the transformer 212 to the temperature control device 116 or to the circulating blower 108 . In response to a refrigerant concentration measurement above the threshold, both the first leak mitigation control module 304 and the second leak mitigation control module 308 bypass the temperature control device 116 and turn the transformer 212 off to the circulating blower 108. ) directly connected to the

3 and 4, the first leakage mitigation control module 304 and the second leakage mitigation control module 308 are located in different spaces of the HVAC system. In various implementations, different circulating blowers can be included in the HVAC system and the second leak mitigation control module 308 can be selectively coupled to the different circulating blowers during mitigation.

A remote monitoring device 312 (or remote control device) may be included and coupled to the first leakage mitigation control module 304 and the second leakage mitigation control module 308 . The remote monitoring device 312 may also be included in implementations having only one leakage mitigation control module. In various implementations, the first leakage mitigation control module 304 and the second leakage mitigation control module 308 may transmit measurements to the remote monitoring device 312 intermittently or in real time. The remote monitoring device 312 may include two-way communication, monitoring the current refrigerant concentration as well as sending commands to the leak sensor or leak mitigation control module 176 to calibrate or reset the leak sensor. . In various implementations, remote monitoring device 312 may be included in temperature control device 116 and/or control module 112 .

The first leakage mitigation control module 304 and the second leakage mitigation control module 308 operate when the threshold is exceeded and the leakage is mitigated (i.e., the first leakage mitigation control module 304 or the second leakage mitigation control module ( If 308) reconnects the control module 112 to the transformer 212), it may also send a notification to the remote monitoring device 312. The remote monitoring device 312 may also send diagnostic information, such as an indication that a refrigerant sensor is malfunctioning or has reached the end of its life. The remote monitoring device 312 may send notifications to a remote device 316, such as a landlord or entity, via WiFi, Bluetooth, ZigBee, Z-Wave, Modbus, BACnet, or any other digital or analog communication channel. Remote device 316 may be a computing device or a mobile computing device. Additionally, remote monitoring device 312 may communicate with temperature control device 116 via a wired or wireless connection (not shown) to monitor HVAC system status.

As discussed above, remote monitoring device 312 can monitor the frequency and magnitude of refrigerant leaks to determine a fault in the HVAC system. In various implementations, the remote monitoring device 312 may generate and transmit alerts to the homeowner or entity in response to the total number of leaks exceeding a threshold number of times over a period of time and the magnitude of each. Remote monitoring device 312 may include a processor, memory and user interface for analyzing, storing and displaying HVAC system data.

In various implementations, the remote monitoring device 312 may also monitor the runtime of the blower during relief. For example, if a blower is operating above a threshold uptime and the refrigerant concentration does not fall below the threshold, remote monitoring device 312 may alert the homeowner or entity that mitigation does not address the refrigerant leak. . Although only two leak mitigation control modules are shown, multiple leak mitigation modules may be included throughout the HVAC system to detect various refrigerant leaks at various locations. In various implementations, leakage mitigation control module 176, first leakage mitigation control module 304, and/or second leakage mitigation control module 308 may include a processor and associated memory and transceiver included in the leakage mitigation control modules. It may include the function of the remote monitoring device 312 through.

7A and 7B are functional block diagrams of leak mitigation control circuitry 404 within the evaporator of an air handling unit. Referring to FIG. 7A , the leakage mitigation control circuit 404 may be implemented as the aforementioned leakage mitigation control module. The leak mitigation control circuit 404 includes a leak sensor 408 and a relay 412 . A leak sensor 408 is connected to the transformer 212 and the first end of the coil 416 of the relay 412. The second end of coil 416 is connected to the second end of transformer 212 . Coil 416 of relay 412 is de-energized in response to leak sensor 408 detecting a refrigerant concentration above a threshold. In various implementations, leak sensor 408 may be a subassembly of leak mitigation control circuitry 404 that includes a separate processor, associated memory, and the like.

The relay includes a common terminal 420, a normally open terminal 424, and a normally closed terminal 428. The common terminal 420 is connected to the first end of the transformer 212 and the control module 112 . An arm 432 of the relay connects the common terminal 412 to the normally closed terminal 428 when the coil 416 is not energized (refrigerant concentration exceeds a threshold value). Arm 432 connects common terminal 412 to normally open terminal 424 when coil 416 is energized (during normal operation with refrigerant concentration below a threshold). Normally open terminal 424 is connected to temperature control device 116 . The second end of transformer 212 is also connected to temperature control device 116 and circulation blower 108 . Transformer 212 is further connected to control module 112 . Therefore, when arm 432 connects common terminal 420 and normally open terminal 424 (when the refrigerant concentration is below the threshold), temperature control device 116 is connected to transformer 212 to supply power to control module 112. and the temperature control device 116 regulates the power flow of the HVAC system components.

When arm 432 connects common terminal 420 to normally closed terminal 428 (in response to the refrigerant concentration exceeding a threshold), transformer 212 supplies power to circulating blower 108 and controls the temperature. Disconnecting device 116 from electrical power prevents control module 112 and HVAC system components from operating.

Referring to FIG. 7B , the leakage mitigation control circuit 404 may be the same except that it includes a double pole double throw (DPDT) relay 450 . DPDT relay 450 includes a first switch 454 having a first normally open terminal 458 and a first normally closed terminal 462 . The second switch 466 includes a second normally open terminal 470 and a second normally closed terminal 474 . When DPDT coil 478 is energized (when the HVAC system is on and the refrigerant concentration is below the threshold), the first switch 454 is connected to the first normally open terminal 458 and the second switch 466 ) is connected to the second normally open terminal 470. This connects the DPDT common terminal 482 to the temperature control device 116. When the refrigerant concentration exceeds the threshold value, the DPDT coil 478 is de-energized, the first switch 454 is connected to the first normally closed terminal 462 and the second switch 466 is connected to the second normally closed terminal Connected to 474, it deactivates the HVAC system components and provides power to the circulation blower 108. Using the DPDT relay 450 provides a backup since both the first normally closed terminal 462 and the second normally closed terminal 474 connect power to the circulating blower 108 . In addition, the first switch 454 and the second switch 466 need to be connected to the first normally open terminal 258 and the second normally open terminal 470, respectively, to enable power supply of HVAC system components. there is. Thus, if one of the contacts accidentally fuses, the other switch will act as a backup to power on the circulating blower 108 and deactivate the HVAC components.

flow chart

8 is a flow diagram illustrating exemplary operation of an exemplary leakage mitigation controller of an HVAC system. Control begins at 504 and measures the refrigerant concentration, for example via the leak sensor 408 described above. Control proceeds to 508 to determine if the measured refrigerant concentration exceeds a threshold, e.g., 25% of the LFL. Otherwise, control returns to 504. Alternatively, if the measured refrigerant concentration exceeds the threshold, control proceeds to 512 to generate and send a leak notification to the homeowner or entity. Control then proceeds to 516 to de-energize relay 412 to disconnect the HVAC system components from power and connect the blower to power. As described above, the relay 412 is switched from a first position connecting the temperature control unit 116 and other HVAC components to electrical power (normally open) to a second position connecting the blower to electrical power (normally closed). Power may be cut off to move 432 .

If the blower is operating, control proceeds to 524 to measure the refrigerant concentration. At 528 the control determines if the refrigerant concentration is below a threshold value. Otherwise, control proceeds to 532 to determine if the current blower uptime is greater than the threshold runtime.

That is, the control determines if the blower has operated beyond the threshold operating time without reducing the refrigerant concentration below the threshold. For example, the critical uptime may be 5 minutes. Otherwise, control returns to 528. Conversely, if the blower operates beyond the critical operating time, control continues to 536. At 536 the control generates and sends an alert notifying that the blower has operated beyond the threshold run time and the refrigerant concentration is still above the threshold. The alert may be sent to the homeowner's user device or the entity's computing system or mobile device.

Once the alert is sent at 536, control returns to 528. Instead, if the refrigerant concentration is below the threshold at 528, control continues at 540. At 540, the control maintains power connection to the blower for a threshold amount of time. Control proceeds to 544 to re-energize the relay to disconnect the blower from power and reconnect the temperature control device to power, to connect the HVAC system components to power. Control proceeds to 548 to generate and transmit a relief complete notification to the homeowner or entity. In various implementations, controls may exclude leakage and mitigation notifications to homeowners or entities. Additionally or alternatively, notifications may be stored locally or on the remote monitoring device 312 described above.

The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, application or use thereof. The broad teachings of this disclosure can be embodied in many forms. Thus, while the present disclosure includes specific examples, the true scope of the disclosure should not be limited to the specific examples as other modifications will become apparent upon a study of the drawings, specification and following claims. It should be understood that one or more steps within a method may be performed in a different order (or concurrently) without altering the principles of the invention. Further, while each embodiment is described above as having particular features, any one or more of these features described for any embodiment of the present disclosure is embodied in and/or combined with features of other embodiments. (even if these combinations are not explicitly described). In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with others are within the scope of the present disclosure.

Spatial and functional relationships between elements (e.g., modules, circuit elements, semiconductor layers, etc.) are "connected", "connected", "coupled", "adjacent", "next", "on top" ", "above", "below" and "disposed" are described using various terms. Unless explicitly stated as "direct", when a relationship between a first element and a second element is described in the above disclosure, the relationship is such that no other intervening place exists between the first element and the second element. It may be a direct relationship, but it may be an indirect relationship where one or more intermediate elements exist (spatially or functionally) between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be interpreted using the non-exclusive logical OR to mean logical (A OR B OR C), meaning "at least one A, at least one of B and at least one C".

In the drawings, the direction of the arrow, indicated by the arrowhead, generally indicates the flow of information (eg, data or instructions) of interest to the description. For example, an arrow may point from element A to element B if element A and element B exchange various information, but the information transmitted from element A to element B is descriptive. This one-way arrow does not mean that no other information is passed from element B to element A. In addition, for information transmitted from element A to element B, element B may send element A a request for the information or an acknowledgment of receipt.

In this application, the term "module" or "control module", including the following definitions, shall be replaced with the term "circuit", in this application, the term "module" or "controller", including the following definitions, "circuit" It can be. The term "module" refers to an Application Specific Integrated Circuit (ASIC); digital, analog or mixed analog/digital discrete circuits; digital, analog or mixed analog/digital integrated circuits; combinational logic circuit; field programmable gate arrays (FPGAs); processor circuitry (shared, dedicated or group) that executes code; memory circuits (shared, dedicated or group) that store code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as a system on a chip;

A module may contain one or more interface circuits. In some examples, the interface circuitry may include a wired or wireless interface coupled to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functionality of any given module of the present disclosure may be distributed among multiple modules connected through interface circuitry. For example, multiple modules can allow for load balancing. In another example, a server (also referred to as remote or cloud) module may perform some functions on behalf of a client module.

The term code as used above may include software, firmware and/or microcode and may refer to programs, routines, functions, classes, data structures and/or objects. The term shared processor circuit includes a single processor circuit that executes some or all of the code of several modules. The term group processor circuit includes a processor circuit that executes some or all of the code of one or more modules along with additional processor circuits. Reference to a multiprocessor circuit includes multiple processor circuits on separate dies, multiple processor circuits on a single die, multiple cores on a single processor circuit, multiple threads on a single processor circuit, or combinations of the above. The term shared memory circuit includes a single memory circuit that stores some or all of the code of several modules. The term group memory circuit includes a memory circuit that stores some or all of the code of one or more modules along with additional memory.

The term memory circuit is a subset of the term computer readable medium. The term computer readable medium as used herein does not include transitory electrical or electromagnetic signals that propagate through the medium (such as a carrier wave); Accordingly, the term computer readable medium may be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer readable media include non-volatile memory circuits (eg, flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (eg, static random access memory circuits). circuits or dynamic random access memory circuits), magnetic storage media (eg analog or digital magnetic tape or hard disk drives) and optical storage media (eg CD, DVD or Blu-ray Disc).

The devices and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more specific functions embodied in a computer program. The function blocks, flowchart components, and other elements described above serve as software specifications that can be converted into computer programs by the routine work of a skilled technician or programmer.

A computer program includes processor executable instructions stored on at least one non-transitory, tangible computer readable medium. A computer program may also include or depend on stored data. A computer program includes a basic input/output system (BIOS) that interacts with the hardware of a special purpose computer, device drivers that interact with specific devices on a special purpose computer, one or more operating systems, user applications, background services, and background applications. can include

A computer program may include: (i) descriptive text to be parsed, such as hypertext markup language (HTML), extensible markup language (XML) or JavaScript Object Notation (JSON), (ii) assembly code, (iii) a compiler. object code generated from source code by (iv) source code executed by an interpreter, (v) source code compiled and executed by a JIT compiler, etc. By way of illustration only, the source code is C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (Hypertext Markup Language 5) languages including Ada, Active Server Pages (ASP), Hypertext Preprocessor (PHP), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic ^® , Lua, MATLAB, SIMULINK and Python ^® can be written using syntax from

Claims (20)

A refrigerant leak detection and mitigation system comprising:
a temperature control device that transmits control signals to the component controller;
a blower to circulate air; and
a leak mitigation controller electrically coupled to the temperature control device;
the leakage mitigation controller directs incoming power to the temperature control device;
The leak mitigation controller:
A sensor that measures the refrigerant concentration;
optionally a relay for (i) connecting the temperature control device to the incoming power or (ii) connecting the blower to the incoming power;
The leak mitigation controller:
measuring the refrigerant concentration with the sensor;
actuate the relay to connect the blower to the incoming power in response to the measured refrigerant concentration exceeding a threshold; composed,
system. According to claim 1,
wherein the relay maintains a connection between the temperature control device and the incoming power through the leak mitigation controller until the measured refrigerant concentration exceeds the threshold.
system. According to claim 1,
The leak mitigation controller:
operating the blower for a threshold time in response to the measured refrigerant concentration falling below the threshold, and controlling the relay in response to passage of the threshold time to connect the temperature control device to the incoming power.
system. According to claim 1,
the temperature control device is selectively connected to the incoming power in a normally open position by the leakage mitigation controller;
the blower is connected to the incoming power in a normally closed position;
The sensor cuts off power to the coil of the relay in response to the measured refrigerant concentration exceeding the threshold value.
system. According to claim 1,
The relay is at least one of (i) a single pole double throw relay, (ii) a double pole double throw relay,
system. According to claim 1,
The relay includes two or more relays or switches,
system. According to claim 1,
The system further comprises a compressor,
wherein the component controller is configured to activate the compressor in response to receiving a control signal indicating a cooling request from the temperature control device.
system. According to claim 1,
The refrigerant at the measured refrigerant concentration is non-toxic and flammable,
system. According to claim 1,
The system further includes a remote monitoring device that interfaces with the leak mitigation controller,
The remote monitoring device is configured to receive the measured refrigerant concentration from the sensor of the leak mitigation controller and store the measured refrigerant concentration together with the corresponding time at which the measured refrigerant concentration was measured,
system. According to claim 9,
The remote monitoring device is configured to monitor the number of times that the coil of the relay is energized, and to generate an alert in response to a number of times that the coil is energized that exceeds a threshold number of times and transmit it to a user device associated with an entity. ,
system. According to claim 9,
The remote monitoring device monitors blower uptime in response to the measured refrigerant concentration exceeding the threshold, and generates an alert in response to the blower uptime exceeding the blower uptime threshold to generate a user device associated with an entity. configured to transmit to
system. According to claim 9,
The remote monitoring device is included in the leak mitigation controller,
system. According to claim 9,
The remote monitoring device is operated by the temperature control device and included in the temperature control device.
system. According to claim 1,
the system further comprises a backup leakage mitigation controller coupled in series with the leakage mitigation controller;
wherein the backup leak mitigation controller is located in a compartment separate from the leak mitigation controller;
system. A heating, ventilation, cooling and/or air conditioning (HVAC-R) system comprising the system of claim 1 . A method for detecting and mitigating refrigerant leaks comprising:
causing incoming power to be provided to the temperature control device through a leakage mitigation controller comprising a sensor and relay;
Measure the refrigerant concentration through the sensor; and,
activating the relay to connect the blower to the incoming power in response to the measured refrigerant concentration exceeding a threshold;
the relay selectively (i) connects the temperature control device to the incoming power or (ii) connects the blower to the incoming power;
Circulating air through the blower,
method. According to claim 16,
the method further comprising using the relay to maintain a connection between the incoming power and the temperature control device through the leakage mitigation controller until the measured refrigerant concentration exceeds the threshold value;
method. According to claim 16,
The method controls the relay to operate the blower for a threshold time in response to the measured refrigerant concentration falling below the threshold and to connect the temperature control device to the incoming power in response to passage of the threshold time. including,
method. According to claim 16,
the method comprising de-energizing a coil of the relay in response to the measured refrigerant concentration exceeding the threshold;
the temperature control device is selectively connected to the incoming power in a normally open position by the leakage mitigation controller;
wherein the blower is connected to the incoming power in a normally closed position;
method. According to claim 16,
The relay is at least one of (i) a single pole double throw relay and (ii) a double pole double throw relay,
method.

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